Electric rotating machine

ABSTRACT

In a dynamoelectric machine according to the present invention, a first three-phase wye-delta hybrid winding and a second three-phase wye-delta hybrid winding are installed in a stator core having a plurality of slots. A first delta U winding portion and a first wye U winding portion are housed in identical slots, a first delta V winding portion and a first wye V winding portion are housed in identical slots, and a first delta W winding portion and a first wye W winding portion are housed in identical slots. A second delta U winding portion and a second wye U winding portion are housed in identical slots, a second delta V winding portion and a second wye V winding portion are housed in identical slots, and a second delta W winding portion and a second wye W winding portion are housed in identical slots.

TECHNICAL FIELD

The present invention relates to a dynamoelectric machine driven by aninternal combustion engine, for example, and mountable to a passengercar, a truck, etc.

BACKGROUND ART

In recent years, improvements in power output have been sought inautomotive alternators due to increases in vehicle loads, and examplesof configurations aiming to achieve such improvements in power outputinclude Japanese Patent Laid-Open No. HEI 5-308751 (Gazette), forexample, which discloses an automotive alternator including twoindependent three-phase stator windings.

However, in such configurations, because two stators are disposedaxially on a shaft, one problem has been that axial dimensions areincreased, increasing overall size.

DISCLOSURE OF INVENTION

The present invention aims to solve the above problems and an object ofthe present invention is to provide a dynamoelectric machine enablingreductions in size to be achieved while ensuring high output.

In order to achieve the above object, according to one aspect of thepresent invention, there is provided a dynamoelectric machine including:a stator core having a plurality of slots extending axially; and a firstthree-phase wye-delta hybrid winding and a second three-phase wye-deltahybrid winding installed in the slots, the first three-phase wye-deltahybrid winding having: a first delta-connected portion in which a firstdelta U winding portion, a first delta V winding portion, and a firstdelta W winding portion are each connected in a delta shape; and asecond wye U winding portion, a second wye V winding portion, and asecond wye W winding portion each connected to the first delta-connectedportion in a Y (wye) shape, the second three-phase wye-delta hybridwinding having: a second delta-connected portion in which a second deltaU winding portion, a second delta V winding portion, and a second deltaW winding portion are each connected in a delta shape; and a first wye Uwinding portion, a first wye V winding portion, and a first wye Wwinding portion each connected to the second delta-connected portion ina Y (wye) shape, the first delta U winding portion and the first wye Uwinding portion being housed in identical slots, the first delta Vwinding portion and the first wye V winding portion being housed inidentical slots, the first delta W winding portion and the first wye Wwinding portion being housed in identical slots, the second delta Uwinding portion and the second wye U winding portion being housed inidentical slots, the second delta V winding portion and the second wye Vwinding portion being housed in identical slots, and the second delta Wwinding portion and the second wye W winding portion being housed inidentical slots.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross section showing a configuration of an automotivealternator according to Embodiment 1 of the present invention;

FIG. 2 is a partially cut-away perspective showing a stator of theautomotive alternator in FIG. 1;

FIG. 3 is a connection diagram showing connections of a single phase ofa stator winding in the automotive alternator in FIG. 1;

FIG. 4 is an electrical circuit diagram for the automotive alternator inFIG. 1;

FIG. 5 is a cross section showing an arrangement of conductors insideslots in a stator core from FIG. 1;

FIG. 6 is a cross section showing an arrangement of conductors insideslots in a stator core of an automotive alternator according toEmbodiment 2 of the present invention;

FIG. 7 is a perspective showing joining between an end portion of awye-connected conductor and end portions of delta-connected conductorsfrom FIG. 6;

FIG. 8 is a perspective showing joining between an end portion of awye-connected conductor and end portions of delta-connected conductorsat a different position than that shown in FIG. 7;

FIG. 9 is a perspective showing joining different than that shown inFIG. 7;

FIG. 10 is a perspective showing joining different than that shown inFIG. 8; and

FIG. 11 is a cross section showing a stator of an automotive alternatoraccording to Embodiment 3 of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

Preferred embodiments of the present invention will now be explainedwith reference to the drawings, and members and portions identical orequivalent in each of the embodiments will be given identical numbering.

Embodiment 1

FIG. 1 is a cross section showing a configuration of an automotivealternator according to Embodiment 1 of the present invention, FIG. 2 isa partial perspective showing a stator from FIG. 1, and FIG. 3 is aconnection diagram showing connections of a single phase of a statorwinding 16 from FIG. 1.

In this automotive alternator, a Lundell-type rotor 7 functioning as afield is rotatably disposed by means of a shaft 6 inside a case 3constituted by a front bracket 1 and a rear bracket 2 made of aluminum.A stator 8 functioning as an armature is disposed so as to be fixed toan inner wall surface of the case 3 around an outer periphery of therotor 7. The shaft 6 is rotatably supported by the front bracket 1 andthe rear bracket 2. A pulley 4 is affixed to a first end portion of theshaft 6 such that rotational torque from an engine can be transmitted tothe shaft 6 by means of a belt (not shown). Slip rings 9 for supplyingan electric current to the rotor 7 are affixed to a second end portionof the shaft 6. A pair of brushes 10 housed inside a brush holder 11slide in contact with the slip rings 9.

A heat sink 17 is fitted onto the brush holder 11. A regulator 18 foradjusting magnitude of an alternating voltage generated in the stator 8is affixed to the heat sink 17 using an adhesive. First and secondrectifiers 12 electrically connected to the stator 8 so as to convert analternating current generated in the stator 8 into a direct current aredisposed inside the case 3.

The rotor 7 is constituted by: a rotor coil 13 for generating magneticflux on passage of an electric current; and first and second pole cores20 and 21 disposed so as to cover the rotor coil 13, magnetic polesbeing formed in the first and second pole cores 20 and 21 by themagnetic flux generated by the rotor coil 13. The first and second polecores 20 and 21 are made of iron, each having eight first and secondclaw-shaped magnetic poles 22 and 23, respectively, disposed on an outerperipheral edge at a uniform angular pitch in a circumferentialdirection so as to project axially, and the first and second pole cores20 and 21 are fixed to the shaft 6 facing each other such that the firstand second claw-shaped magnetic poles 22 and 23 intermesh.

Fans 5 are affixed to first and second axial end surfaces of the rotor7. Front-end and rear-end air intake apertures 1 a and 2 a are formed onfirst and second end surfaces of the front bracket 1 and the rearbracket 2. Front-end and rear-end air discharge apertures 1 b and 2 bare formed on first and second shoulder portions of the front bracket 1and the rear bracket 2.

The stator 8 includes: a stator core 15 constituted by a cylindricallaminated core in which a plurality of slots 15 a extending axially areformed at a predetermined pitch circumferentially; a stator winding 16installed in the stator core 15; and insulators 19 mounted inside eachof the slots 15 a so as to insulate electrically between the statorwinding 16 and the stator core 15.

The stator winding 16 is constituted by a first three-phase wye-deltahybrid winding 160 a and a second three-phase wye-delta hybrid winding160 b, as can be seen from an electrical circuit diagram shown in FIG.4.

The first three-phase wye-delta hybrid winding 160 a and the secondthree-phase wye-delta hybrid winding 160 b are installed in the slots 15a of the stator core 15 so as to have a phase difference correspondingto an electrical angle of approximately 30 degrees.

A stator winding phase portion 161 constituted by the first three-phasewye-delta hybrid winding 160 a and the second three-phase wye-deltahybrid winding 160 b is constituted by first through sixth windingsub-portions 31 through 36 each constituted by one continuous wire 30,as can be seen from the connection diagram shown in FIG. 3.

The first winding sub-portion 31 is configured into a single-turnfull-pitch wave winding by winding a continuous wire 30 constituting aconductor into a full-pitch wave winding so as to alternately occupy afirst position from an inner periphery (hereinafter called “Address 1”)and a second position from the inner periphery (hereinafter called“Address 2”) inside the slots 15 a in every sixth slot in Slot Numbers 1through 91, and joining together end portions of the continuous wire 30.

The second winding sub-portion 32 is configured into a single-turnfull-pitch wave winding by winding a continuous wire 30 into afull-pitch wave winding so as to alternately occupy Address 2 andAddress 1 inside the slots 15 a in every sixth slot in Slot Numbers 1through 91, and joining together end portions of the continuous wire 30.

The third winding sub-portion 33 is configured into a single-turnfull-pitch wave winding by winding a continuous wire 30 into afull-pitch wave winding so as to alternately occupy a third positionfrom the inner periphery (hereinafter called “Address 3”) and a fourthposition from the inner periphery (hereinafter called “Address 4”)inside the slots 15 a in every sixth slot in Slot Numbers 1 through 91,and joining together end portions of the continuous wire 30.

The fourth winding sub-portion 34 is configured into a single-turnfull-pitch wave winding by winding a continuous wire 30 into afull-pitch wave winding so as to alternately occupy Address 4 andAddress 3 inside the slots 15 a in every sixth slot in Slot Numbers 1through 91, and joining together end portions of the continuous wire 30.The fifth winding sub-portion 35 is configured into a single-turnfull-pitch wave winding by winding a continuous wire 30 into afull-pitch wave winding so as to alternately occupy a fifth positionfrom the inner periphery (hereinafter called “Address 5”) and a sixthposition from the inner periphery (hereinafter called “Address 6”)inside the slots 15 a in every sixth slot in Slot Numbers 1 through 91,and joining together end portions of the continuous wire 30.

The sixth winding sub-portion 36 is configured into a single-turnfull-pitch wave winding by winding a continuous wire 30 into afull-pitch wave winding so as to alternately occupy Address 6 andAddress 5 inside the slots 15 a in every sixth slot in Slot Numbers 1through 91, and joining together end portions of the continuous wire 30.

In each of the slots 15 a, six conductor wires 30 are arranged so as toline up in one column radially with longitudinal axes of rectangularcross sections aligned radially.

Thus, each of the continuous wire 30 constituting the first throughsixth winding sub-portions 31 through 36 is installed in a full-pitchwave winding so as to project outward from one slot 2 a at an endsurface of the stator core 2, turn around, and enter a slot 15 a sixslots away, and is installed so as to alternately occupy an inner layerand an outer layer in a slot depth direction (radially) inside the slots15 a in every sixth slot.

Return portions 30 a of the continuous wires 30 projecting outward andturning around at the end surfaces of the stator core 15 form coil endportions. The return portions 30 a, which are formed so as to have agenerally uniform shape, are separated from each other circumferentiallyand radially, and arranged circumferentially in three neat layers,forming front-end and rear-end coil ends 16 f and 16 r at first andsecond ends of the stator core 15.

In this embodiment, portions of the continuous wires 30 of the second,fourth, and sixth winding sub-portions 32, 34, and 36 projecting outwardfrom Slot Numbers 61 and 67 at the first end of the stator core 15 arecut, portions of the continuous wires 30 of the first, third, and fifthwinding sub-portions 31, 33, and 35 projecting outward at the first endof the stator core 15 from Slot Numbers 67 and 73 are cut, and a firstcut end portion 31 a of the first winding sub-portion 31 and a secondcut end portion 32 b of the second winding sub-portion 32 are joinedtogether to form a two-turn first series-connected winding portion 162 ain which the first and second winding sub-portions 31 and 32 areconnected in series. A second cut end portion 31 b at an opposite end ofthe first winding sub-portion 31 from the first cut end portion 31 a anda first cut end portion 32 a at an opposite end of the second windingsub-portion 32 from the second cut end portion 32 b project axiallyoutward from the stator core 15.

Similarly, a first cut end portion 33 a of the third winding sub-portion33 and a second cut end portion 35 b of the fifth winding sub-portion 35are joined together, a first cut end portion 34 a of the fourth windingsub-portion 34 and a second cut end portion 36 b of the sixth windingphase sub-portion 36 are joined together, and a first cut end portion 35a of the fifth winding sub-portion 35 and a second cut end portion 34 bof the fourth winding sub-portion 34 are joined together to form afour-turn second series-connected winding portion 162 b in which thethird, fourth, fifth, and sixth winding sub-portions 33, 34, 35, and 36are connected in series. A second cut end portion 33 b at an oppositeend of the third winding sub-portion 33 from the first cut end portion33 a and a first cut end portion 36 a at an opposite end of the sixthwinding sub-portion 36 from the second cut end portion 36 b projectaxially outward from the stator core 15.

A single phase portion of the stator winding 16 is formed in thismanner, and another five phase portions are also formed similarly whileoffsetting the slots 15 a into which the continuous wires 30 areinstalled by one slot each.

The four-turn second series-connected winding portions 162 b eachconstitute a first delta U winding portion 50 a, a second delta Uwinding portion 50 b, a first delta V winding portion 51 a, a seconddelta V winding portion 51 b, a first delta W winding portion 52 a, anda second delta W winding portion 52 b, respectively, as shown in FIG. 4.

The two-turn first series-connected winding portions 162 a eachconstitute a first wye U winding portion 53 a, a second wye U windingportion 53 b, a first wye V winding portion 54 a, a second wye V windingportion 54 b, a first wye W winding portion 55 a, and a second wye Wwinding portion 55 b, respectively.

In the first three-phase wye delta hybrid winding 160 a, the first deltaU winding portion 50 a, the first delta V winding portion 51 a, and thefirst delta W winding portion 52 a are all connected in a delta shape toconstitute a first delta-connected portion, and the second wye U windingportion 53 b, the second wye V winding portion 54 b, and the second wyeW winding portion 55 b are each connected to the first delta-connectedportion in a Y (wye) shape. Second end portions of the second wye Uwinding portion 53 b, the second wye V winding portion 54 b, and thesecond wye W winding portion 55 b are each connected to the firstrectifier 12 by means of output wires 70 having a circular crosssectional shape.

In the second three-phase wye delta hybrid winding 160 b, the seconddelta U winding portion 50 b, the second delta V winding portion 51 band the second delta W winding portion 52 b are all connected in a deltashape to constitute a second delta connected portion, and the first wyeU winding portion 53 a, the first wye V winding portion 54 a, and thefirst wye W winding portion 55 a are each connected to the second deltaconnected portion in a Y (wye) shape. Second end portions of the firstwye U winding portion 53 a, the first wye V winding portion 54 a, andthe first wye W winding portion 55 a are each connected to the secondrectifier 12 by means of output wires 70.

The first delta U winding portion 50 a and the first wye U windingportion 53 a are housed in identical slots 15 a to each other (first setof slots 15 a), as shown in FIG. 5. The second delta-U winding portion50 b and the second wye U winding portion 53 b are housed in identicalslots 15 a to each other in a second set of slots 15 a to the right ofthe first set of slots 15 a.

In FIG. 5, although not shown, the first delta V winding portion 51 aand the first wye V winding portion 54 a, the second delta V windingportion 51 b and the second wye V winding portion 54 b, the first deltaW winding portion 52 a and the first wye W winding portion, and thesecond delta W winding portion 52 b and the second wye W winding portion55 b are also housed sequentially in third through sixth sets of slots15 a in a clockwise direction.

Thus, the winding portions of identical phases of the first three-phasewye-delta hybrid winding 160 a and the second three-phase wye-deltahybrid winding 160 b are housed sequentially in order of a U phase, a Vphase, and a W phase in each of the sets of slots 15 a in a clockwisedirection.

Inside each of the slots 15 a, the wye-connected conductors constitutingthe first wye U winding portion 53 a, the second wye U winding portion53 b, the first wye V winding portion 54 a, the second wye V windingportion 54 b, the first wye W winding portion 55 a, and the second wye Wwinding portion 55 b, respectively, are disposed radially further inwardthan the delta-connected conductors constituting the first delta Uwinding portion 50 a, the second delta-U winding portion 50 b, the firstdelta V winding portion 51 a, the second delta V winding portion 51 b,the first delta W winding portion 52 a, and the second delta W windingportion 52 b, respectively, as shown in FIG. 5.

The output wires 70 connected to the rectifiers 12 project outward fromthe innermost layer inside the slots 15 a.

In an automotive alternator configured in this manner, an electriccurrent is supplied to the rotor coil 13 from a battery (not shown) bymeans of the brushes 10 and the slip rings 9, generating a magneticflux. The first claw-shaped magnetic poles 22 in the first pole core 20are magnetized into North-seeking (N) poles by this magnetic flux, andthe second claw-shaped magnetic poles 23 in the second pole core 21 aremagnetized into South-seeking (S) poles. At the same time, therotational torque from the engine is transmitted to the shaft 6 by meansof the belt (not shown) and the pulley 4, rotating the rotor 7. Thus, arotating magnetic field is imparted to the stator winding 16, generatingan electromotive force in the stator winding 16. Thisalternating-current electromotive force passes through the rectifiers 12so as to be converted into a direct current, the current is combined,and then the magnitude thereof is adjusted by the regulator 18 andcharged to the battery.

Due to rotation of the fans 5 secured to the first and second axial endsurfaces of the rotor 7, at a rear bracket 2 end, external air is drawnin through the rear-end air intake apertures 2 a, cooling the rectifiers12 and the regulator 18, is then deflected centrifugally by the fans 5,cooling the rear-end coil ends 16 r of the stator winding 16, and isdischarged externally through the rear-end air discharge apertures 2 b.

At a front bracket 1 end, external air is drawn in through the front-endair intake apertures 1 a, is then deflected centrifugally by the fans 5,cooling the front-end coil ends 16 f of the stator winding 16, and isdischarged externally through front-end air discharge apertures 1 b.

In an automotive alternator according to this embodiment, the firstthree-phase wye-delta hybrid winding 160 a and the second three-phasewye-delta hybrid winding 160 b are installed in a single stator core 15,enabling axial dimensions to be shortened unlike conventionalconfigurations having a plurality of stators, and the automotivealternator can be reduced in size. Operations required conventionallyfor wiring between stators are also no longer necessary, enabling wiringoperations to be performed simply on top of the coil ends 16 r of thestator winding 16.

The first three-phase wye-delta hybrid winding 160 a and the secondthree-phase wye-delta hybrid winding 160 b are disposed so as to have aphase difference corresponding to an electrical angle of approximately30 degrees, canceling out fifth and seventh harmonic components ofmagnetic vibrational force and reducing electromagnetic noise.

Because the stator winding phase portions 161 are constituted byfull-pitch windings, the fifth and seventh harmonic components ofmagnetic vibrational force are canceled out completely, reducingelectromagnetic noise.

Moreover, similar effects are also exhibited if all of the windingportions are constituted by short-pitch windings and configured suchthat conductors in all of the slots are equal in number.

Because the alternating-current outputs from the first three-phasewye-delta hybrid winding 160 a and the second three-phase wye-deltahybrid winding 160 b are independently rectified by the first and secondrectifiers 12, respectively, then combined and outputted, high-outputelectric power can be achieved.

The fifth and seventh harmonic components of magnetic vibrational forceare canceled out completely if a turn ratio between the wye-connectedconductors and the delta-connected conductors is 1:√3, but since it isdifficult to set the turn ratio exactly to 1:√3, the wye-connected firstseries-connected winding portions 162 a are set to two turns, and thedelta-connected second series-connected winding portions 162 b to fourturns.

In this embodiment, by setting the turn ratio to an integer ratio closeto 1:√3, that is, 1:2, even if the first three-phase wye-delta hybridwinding 160 a breaks down, electromagnetic noise is kept low andpassengers will not experience any great discomfort because the fifthand seventh harmonic components of magnetic vibrational force are stillcanceled out by operation of the second three-phase wye-delta hybridwinding 160 b.

Since the winding sub-portions 31 through 36 are configured byinstalling continuous wires 30 in wave windings in every sixth slot soas to alternately occupy inner layers and outer layers in a slot depthdirection (radially) inside the slots 15 a and the continuous wires 30are separated into delta-connected conductors and wye-connectedconductors having an even number of turns in each of the windingsub-portions 31 through 36, windability is good.

Since the continuous wires 30 are disposed inside the slots 15 a withlongitudinal directions of rectangular cross sections aligned radially,space factor is high, improving output efficiency of the automotivealternator.

Because the winding portions 53 a, 53 b, 54 a, 54 b, 55 a, and 55 b ofthe wye-connected portions, in which the electric current density ishigh, are disposed radially inside the stator core 15 and are near thefans 5, the winding portions 53 a, 53 b, 54 a, 54 b, 55 a, and 55 b ofthe wye-connected portions having a high current density are cooledefficiently, preventing temperature distribution in the stator winding16 from becoming nonuniform.

Because the output wires 70 connected to the rectifiers 12 projectoutward from the innermost layer inside the slots 15 a, sufficientdistance can be ensured between the output wires 70 and the rear bracket2 to prevent current leakage between the output wires 70 constitutingalternating-current output terminals and the rear bracket 2 constitutinggrounding, enabling rusting or electrolytic corrosion to be prevented.

Moreover, because the stator core 15 fits together with an innerperipheral side of a front bracket 1 and a rear bracket 2 made ofaluminum, conductors of the wye-connected portions, which have a highercurrent density, may also be disposed on a radially-outer side and behoused inside the slots such that three sides of the rectangularconductors disposed radially outermost are placed almost withoutclearance in close contact with inner wall surfaces of the slots 15 awith insulators 19 interposed.

In that case, heat generated in the wye-connected conductors isdischarged externally through the stator core and the brackets,efficiently cooling the wye-connected conductors.

Conductor cooling effects may also be further improved by formingradiating fins on outer peripheral surfaces of the bracket in thevicinity of the stator core.

Embodiment 2

FIG. 6 is a partial cross section of an automotive alternator accordingto Embodiment 2 of the present invention.

In an automotive alternator according to Embodiment 2, a first delta Uwinding portion 150 a, a second delta U winding portion 150 b, a firstdelta V winding portion, a second delta V winding portion, a first deltaW winding portion, and a second delta W winding portion are constitutedby two turns of first continuous wires constituting delta-connectedconductors, and a first wye U winding portion 153 a, a second wye Uwinding portion 153 b, a first wye V winding portion, a second wye Vwinding portion, a first wye W winding portion, and a second wye Wwinding portion 155 b are constituted by two turns of second continuouswires constituting wye-connected conductors made of a conductor having adifferent cross-sectional area to that of the first continuous wires.

The cross-sectional area of the conductors of the second continuouswires is configured so as to be greater than the cross-sectional area ofthe conductors of the first continuous wires by a factor ofapproximately √3.

In an automotive alternator according to Embodiment 2, the electriccurrent density arising in the winding portions 150 a, 150 b, and 152 bin the delta-connected portions and the electric current density arisingin the winding portions 153 a, 153 b, and 155 b in the wye-connectedportions are generally equal, making temperature distribution in thestator winding 16 generally uniform.

First wye end portions 132 a of each of the second wye U winding portion153 b, the second wye V winding portion, and the second wye W windingportion 155 b connected in a Y (wye) shape to respective delta-connectedportions project outward in straight lines axially from the stator core15, and first and second surfaces of the first wye end portions 132 aare joined together by surface contact with first and second delta endportions 133 b and 136 a of the first delta U winding portion 150 b, thefirst delta V winding portion, and the first delta W winding portion,respectively, as shown in FIG. 7.

At other positions connected to the delta-connected portions in a Y(wye) shape, the first and second delta end portions 133 b and 136 a arejoined together by surface contact with a first or second surface of thefirst wye end portions 132 a, as shown in FIG. 8.

Moreover, each of the end portions 132 a, 133 b and 136 a, which aremade of an oxygen-free copper, may also be joined together using TIG(tungsten inert gas) welding with flat surfaces in contact with eachother.

Because the first wye and first and second delta end portions 132 a, 133b, and 136 a are joined together with each other by fusion welding usingsurface contact in this manner, and the contact surface area is large,heat generation in the first wye and first and second delta end portions132 a, 133 b, and 136 a can be suppressed.

Since the first wye end portions 132 a of each of the second wye Uwinding portion 153 b, the second wye V winding portion, and the secondwye W winding portion 155 b project outward from the rear-end coil ends16 r axially, the first wye end portions 132 a will not be damaged bypeeling of coatings.

The first wye end portions 132 a are reinforced by the first and seconddelta end portions 133 b and 136 a, and the first wye and first andsecond delta end portions 132 a, 133 b, and 136 a are joined firmly toeach other.

Moreover, as shown in FIGS. 9 and 10, a first wye end portion 132 a, asecond delta end portion 133 b, and a first delta end portion 136 a mayalso be joined together firmly to each other by surrounding and pressurewelding them using a belt-shaped ring 60 made of a carbon steel sheet towhich a thin film of tin is bonded.

Moreover, the second delta end portions 133 b and the first delta endportions 136 a, which have a quadrilateral cross sectional shape, mayalso be given a circular cross sectional shape. In that case, bendingdeformation of the second delta end portions 133 b and the first deltaend portions 136 a having a circular cross sectional shape becomespossible in any direction, improving wiring connection freedomproportionately.

In FIGS. 7 through 10, joining between the delta-connected portions andthe first wye end portions 132 a of the second wye U winding portion 153b, the second wye V winding portion, and the second wye W windingportion 155 b, respectively, has been explained, but the delta-connectedportions and the first wye end portions of the first wye U windingportion, the first wye V winding portion, and the first wye W windingportion, respectively, are also joined together in a similar manner.

Embodiment 3

FIG. 11 is a partial cross section of an automotive alternator accordingto Embodiment 3 of the present invention.

In an automotive alternator according to Embodiment 3, wye coil endportions 120 a being coil ends of wye-connected portions disposed on aradially-inner side of a stator winding 16 are axially longer than deltacoil end portions 120 b being coil ends of delta-connected portionsdisposed on a radially-outer side.

In this manner, the wye coil end portions 120 a, which have higherelectric current density, are placed nearer to centrifugal fans 5,colliding flow of cooling airflow is increased, and the wye-connectedportions are cooled even more efficiently, preventing temperaturedistribution in the stator winding 16 from becoming nonuniform.

Moreover, in each of the above embodiments, the winding sub-portions areeach constituted by a continuous wire, but winding sub-portions may alsobe configured by connecting together a plurality of conductor segmentsformed so as to have a general U shape made up of: a pair of straightportions housed inside slots; a linking portion linking the straightportions with each other; and joining portions disposed on leading endportions of the straight portions and projecting outward from an endsurface of a stator core.

An automotive alternator has been explained as an example of adynamoelectric machine, but of course the present invention can also beapplied to any dynamoelectric machine such as an electric motor, agenerator-motor, etc.

1. A dynamoelectric machine comprising: a stator core having a pluralityof slots extending axially; and a first three-phase wye-delta hybridwinding and a second three-phase wye-delta hybrid winding installed insaid slots, said first three-phase wye-delta hybrid winding having: afirst delta-connected portion in which a first delta U winding portion,a first delta V winding portion, and a first delta W winding portion areconnected in a delta shape; and a second wye U winding portion, a secondwye V winding portion, and a second wye W winding portion each connectedto said first delta-connected portion in a Y (wye) shape, said secondthree-phase wye-delta hybrid winding having: a second delta-connectedportion in which a second delta U winding portion, a second delta Vwinding portion, and a second delta W winding portion are connected in adelta shape; and a first wye U winding portion, a first wye V windingportion, and a first wye W winding portion each connected to said seconddelta-connected portion in a Y (wye) shape, said first delta U windingportion and said first wye U winding portion being housed in identicalslots, said first delta V winding portion and said first wye V windingportion being housed in identical slots, said first delta W windingportion and said first wye W winding portion being housed in identicalslots, and said second delta U winding portion and said second wye Uwinding portion being housed in identical slots, said second delta Vwinding portion and said second wye V winding portion being housed inidentical slots, and said second delta W winding portion and said secondwye W winding portion being housed in identical slots.
 2. Thedynamoelectric machine according to claim 1, wherein: said firstthree-phase wye-delta hybrid winding and said second three-phasewye-delta hybrid winding are installed in said slots of said stator coreso as to have a phase difference corresponding to an electrical angle ofapproximately 30 degrees.
 3. The dynamoelectric machine according toclaim 2, wherein: each of said winding portions is constituted by aconductor in a full-pitch winding; and an equal number of conductors arehoused in each of said slots.
 4. The dynamoelectric machine according toclaim 3, wherein: said first three-phase wye-delta hybrid winding andsaid second three-phase wye-delta hybrid winding are electricallyconnected separately to respective rectifiers.
 5. The dynamoelectricmachine according to claim 1, wherein: a ratio between turns ofconductors in said first wye U winding portion, said first wye V windingportion, said first wye W winding portion, said second wye U windingportion, said second wye V winding portion, and said second wye Wwinding portion and turns of conductors in said first delta U windingportion, said first delta V winding portion, said first delta W windingportion, said second delta U winding portion, said second delta Vwinding portion, and said second delta W winding portion is 1:2.
 6. Thedynamoelectric machine according to claim 1, wherein: turns ofconductors in said winding portions are even in number.
 7. Thedynamoelectric machine according to claim 1, wherein: a ratio between across-sectional area inside said slots of wye-connected conductorsconstituting said first wye U winding portion, said first wye V windingportion, said first wye W winding portion, said second wye U windingportion, said second wye V winding portion, and said second wye Wwinding portion and a cross-sectional area inside said slots ofdelta-connected conductors constituting said first delta U windingportion, said first delta V winding portion, said first delta W windingportion, said second delta U winding portion, said second delta Vwinding portion, and said second delta W winding portion is √3:1.
 8. Thedynamoelectric machine according to claim 7, wherein: said wye-connectedconductors have a substantially quadrilateral-shaped cross-sectionalarea in which a radial length is a long side and a circumferentiallength is a short side; said delta-connected conductors have asubstantially quadrilateral-shaped cross-sectional area; and saidwye-connected conductors and said delta-connected conductors arearranged in single columns radially inside said slots.
 9. Thedynamoelectric machine according to claim 1, wherein: a fan for coolingsaid stator winding is mounted to an end surface of a rotor rotatablydisposed inside said stator; and wye-connected conductors constitutingsaid first wye U winding portion, said first wye V winding portion, saidfirst wye W winding portion, said second wye U winding portion, saidsecond wye V winding portion, and said second wye W winding portion aredisposed radially further inward inside each of said slots thandelta-connected conductors constituting said first delta U windingportion, said first delta V winding portion, said first delta W windingportion, said second delta U winding portion, said second delta Vwinding portion, and said second delta W winding portion.
 10. Thedynamoelectric machine according to claim 1, wherein: wye-connectedconductors constituting said first wye U winding portion, said first wyeV winding portion, said first wye W winding portion, said second wye Uwinding portion, said second wye V winding portion, and said second wyeW winding portion are disposed radially further outward inside each ofsaid slots than delta-connected conductors constituting said first deltaU winding portion, said first delta V winding portion, said first deltaW winding portion, said second delta U winding portion, said seconddelta V winding portion, and said second delta W winding portion; andsaid wye-connected conductors are housed inside said slots such thatthree sides of a rectangular cross section of wye-connected conductorsdisposed on a radially-outermost side are in close contact with innerwall surfaces with an insulator interposed.
 11. The dynamoelectricmachine according to claim 1, wherein: end portions of said first wye Uwinding portion, said first wye V winding portion, said first wye Wwinding portion, said second wye U winding portion, said second wye Vwinding portion, and said second wye W winding portion project outwardfrom a radially-innermost side inside said slots; and said end portionsare electrically connected to a rectifier disposed radially inside saidstator by means of output wires.
 12. The dynamoelectric machineaccording to claim 11, wherein: said output wires have a circular crosssectional shape.
 13. The dynamoelectric machine according to claim 1,wherein: a wye end portion of said second wye U winding portion, saidsecond wye V winding portion, and said second wye W winding portionconnected to said first delta-connected portion in a Y (wye) shapeprojects outward from said stator core in a straight line axially andhas a rectangular cross-sectional shape; delta end portions of saidfirst delta U winding portion, said first delta V winding portion, andsaid first delta W winding portion connected to said wye end portionhave a rectangular cross-sectional shape; and said wye end portion andsaid delta end portions are joined together with each other by surfacecontact.
 14. The dynamoelectric machine according to claim 1, wherein: awye end portion of said second wye U winding portion, said second wye Vwinding portion, and said second wye W winding portion connected to saidfirst delta-connected portion in a Y (wye) shape projects outward fromsaid stator core in a straight line axially and has a rectangularcross-sectional shape; delta end portions of said first delta U windingportion, said first delta V winding portion, and said first delta Wwinding portion connected to said wye end portion have a circularcross-sectional shape; and said wye end portion and said delta endportions are joined together with each other.
 15. The dynamoelectricmachine according to claim 13, wherein: said wye end portion and saiddelta end portions are surrounded by a ring made of a carbon steel sheetcoated with tin; and said wye end portion and said delta end portionsare joined together by pressure from said ring.
 16. The dynamoelectricmachine according to claim 1, wherein: a fan for cooling said statorwinding is mounted to an end surface of a rotor rotatably disposedinside said stator; a coil end of said stator winding projecting axiallyoutward from an end surface of said stator core comprises: a wye coilend portion being a coil end portion of said first wye U windingportion, said first wye V winding portion, said first wye W windingportion, said second wye U winding portion, said second wye V windingportion, and said second wye W winding portion; and a delta coil endportion being a coil end portion of said first delta U winding portion,said first delta V winding portion, said first delta W winding portion,said second delta U winding portion, said second delta V windingportion, and said second delta W winding portion; and an axial length ofsaid wye coil end portion is longer than an axial length of said deltacoil end portion.